Drilling machine



Nov. 17, 1936.

E. G. LEWIS 2,060,814 I DRILLING MACHINE Filed Aug. 18, 1932 4 Sheets-Sheet 1 flvvavrolz Elm/A20 G. Lew/s.

Nov. '17, 1 936. E. G. LEWIS DRILLING MACHINE 4 Sheets-Shes; 2

Filed Aug. "18, 19:52

l/vvs/vroe EDWARD G. LEW/5.

4 She'ets-Sheet 3 Nov. 17, 1936. E. G. LEWIS DRILLING MACHINE Filed Au 18, 1932 Nov. 17, 1936. E. G. LEWIS DRILLI NG MACHINE a 4 Sheets-Sheet 4 Filed Aug. 18, 1932 I/vvE/v op: fpwmzp G. LEWIS.

Patented Nov. 17, 1936 srATEs PATNT FiCE DRILLING MACHINE Edward G. Lewis, Columbus, Ohio, assignor to The .llefiirey Manufacturing Company, a corporation of Ohio My invention relates to a track mounted drilling machine particularly adapted for use in coal mines although it may. have a general application.

An object of the present invention is to provide improved and efficient apparatus'for enabling a track mounted drilling machine to drill holes in advance of a mine track at various elevations at the working face either at or near the floor or at or near the roof of the mine chamher or at intermediate points and also at various points extending from the floor to the roof near the ribs or-side walls of the entry in which the mine track is laid.

Another object of my invention is the provision oi improved and efiicient controlling and adjusting mechanism to enable the drill to be operated in any one of many different positions at an up right working race.

A further object of the invention is the pi: vision of fluid pressure mechanism for feeding a rotary drill and for withdrawing the same from the drill hole.

Another object of the invention is to provide motor-operated mechanism including fluid pres-' sure motors for adjusting and operating the rotary drill and controlling such adjustment and operation by interlocking mechanism to prevent interference between adjustments of the drill and the operations thereof.

A still further objectof the invention is to provide drilling apparatus embodying more emcient and economical construction which shall he more convenient in operation than previously known drilling apparatus.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the claims hereto appended.

in the accompanying drawings Fig. l is an elevational view of the complete track mounted machine;

Fig. 2 is a plan view of the construction shown in Fig. l;

Fig. 3 is a plan view of the drilling mechanism mounted on a turntable but detached from the truck, parts in section showing the gearing for driving the main drill shaft;

Fig. is an enlarged vertical sectional View taken on the line lil of Fig. 2 looking in the direction of the arrows;

Fig. 5 is an enlarged vertical sectional view taken on the line 5-5 of Fig. 1 looking in the direction of the arrows;

Fig. 6 is a vertical sectional view taken on the line 6--5 of Fig. 3 looking in the direction of the arrows;

Fig. '7 is a diagrammatic view showing the controlling apparatus forthe hydraulic motor; and

Fig. 8 is a diagrammatic view similar to Fig. '7 5 to show in comparison with the latter the interlocking mechanism to prevent both,hydraulic motors from being operated at the same time.

In Figs. 1 and 2 I have shown the drilling apparatus mounted upon a truck generally des- 10 ignated by the reference number 9, this truck being provided with wheels it which are adapted to travel on a mine track it which may extend along an entry in a coal mine between the ribs or walls adjacent an upright working face in advance of the mine track.

Mounted on the truck 9 is an electric motor 52 the armature of which is connected to a pinion id meshing with the gear id keyed to a shaft it which carries a sprocket connected by a sprocket chain it meshing with a larger sprocket keyed to the rear axle ll of the truck. A suitable controller i8 operated'by a handle is and comprising resistance in the motor circuit in a well-known manner, may be provided to start, stop, reverse and control the speed of the motor l2 so that the truck propelling mechanism may be operated either at a transport speed or at a drill feeding speed.

Also keyed to the shaft i5 is a sheave wheel which is connected by means of the endless rope it to a larger sheave wheel 22 for driving the reel to on which the electric cable it is wound for the puropse of connecting the electric motors it and 2'5 on the drilling machine to a distant source of electric power supply in accordance with the position of the truck: on the mine track in the mine. It should be understood that the motor it may be reversed so as to effect propulsion of the a truck and driling apparatus in either direction along the mine track l l, the reel 23 being rotated in the proper direction to wind up or pay out the cable 24% in accordance with the direction of travel of the truck.

The motor 02 is mounted in a frame 26 which is secured to the top of the truck frame 9. Securedvto the top of the frame 26 is a, semi-circular plate and extends loosely through an opening 33 in the turntable plate 28. The nut 3| is provided with a cylindrical extension 34 which fits into the circular hole in the stationary plate 21. A washer 35 surrounds the tube 36 and is located between the top of the nut extension 34 and the bottom edges of the hole 33. The ball-bearing 38 is located in an inverted circular channel in the housing 23.

Distributed along the forward peripheral portion of the turntable 28 is a plurality of circumferentially spaced-apart supporting rollers 31, 31 each mounted in a housing 38 as shown in Figs. 8 and 6. The housings 38 are bolted to the tumtable 28 as indicated at 38, 38 in Fig. 6. Each roller 31 is provided with a bushing 48 ioumalled on the bearing pin 4|.

Secured to the top of the turntable 28 is a cradle comprising vertical spaced-apart supporting plates 42, 42 one of which is shown in elevation in Fig. 1. The drilling unit 43 is pivoted at 44 to the upper forward ends of the cradle plates 42 as shown in Figs. 1 and 4.

The drilling unit 43 comprises an electric motor 25 to the frame 45 of which is provided with spaced-apart bosses 48,'46 as shown in Fig. 3. A rod 41 extends through holes in the bosses 48 and through holes in the upper forward ends of the plates 42. Lock nuts 48, 48 on the outer ends of the rod 41 outside of the plates 42 hold the rod 41 in proper position to serve as journal bearings for the bosses 46 which fit between the inner sides of the plates 42. It will thus be seen that the drilling unit 43 is pivoted to the turntable for up and down tilting movements relatively thereto on a horizontal axis in the various positions to which the turntable is rotated on the vertical axis of the pivotal connection at 38 between the turntable 28 and the stationary frame 21 which is secured to the truck frame 8. V

Atthe rear end of the drill unit 43 on a platform 48 which is secured rigidly to the motor frame 45, is mounted a hydraulic pump 58 to which is connected a flexible hose 5|. The hydraulic pump 58 is operatively connected to the electric motor 25 by means of the pinion 52 on the armature shaft and the gear 53 on the hydraulic pump shaft. The forward end of the arm'ature shaft of the electric motor 25 is provided with a pinion 54 which meshes with the gear 55 keyed to a countershaft 58 to which is also keyed a pinion 51 meshing with a gear 58. The reduction gearing comprising the gears 54, 55, 51 and 58 is mounted in a housing 58 secured rigidly to the frame 45. The motor 25 and the reduction gearing are entirely enclosed.

I prefer to pivot the drilling unit 43 on the; upper side thereof as indicated at 44 in Fig. 1,

so as to reduce the overall height of the machine and enable the latter to operate in relatively low roof mine chambers. As shown in Fig. 4, the pump and the rear portion of the motor 25 are located at the rear end of the support 45, 63 for the motor 25 and the boom 6|. The placing of the motor 25 and the pump 58 at the rear end of the drilling unit 43 assists in counterbalancing the latter on a transverse axis 41 and consequently the power necessary for operating the hydraulic motor I38 is reduced. Furthermore, by counterbalancing the drilling unit it may more easily be held in adjusted position when the piston I38 is locked in the cylinder |3|.

As shown in Fig. 4 the gear 58 is keyed to a driving shaft 88 which extends longitudinally a gear housing 84. A tubular bushing 85 lines 5 the inner wall of the frame 83 and is provided with an annular flange 66 in the housing 84. The rear end of the tubular boom or arm 8| is Journalled in the bushing 65.

A sleeve 81 fits into a counterbore against the 10 annular shoulder 68. The rear end of the sleeve 81 has keyed thereto a bushing 88 in which is journalled the rear end of the driving shaft 88.

A worm gear 18 is secured by means of keys 1| to the sleeve 81 and the tubular boom or arm 15 8| so as to rotate with the sleeve and boom. A

washer 12 is located between the rear face of the worm gear 18 and the front face of the annular flange 88. It should be understood that the worm gear 18 is keyed to both the sleeve 81 and the tu- 20 bular boom or arm 8 I so that whenever the worm gear 18 rotates both the sleeve 61 and the boom 8| will rotate with the same. A worm 13 in the lower portion of the housing 84 meshes with the worm gear 18. The shaft 14 for the worm 13 25 extends to a position outside of the housing 84 and has connected thereto a crank 15 by means of which the worm 13 and the worm gear 18 may be rotated which in turn will effect the rotation of the sleeve 81 and the tubular boom 6| on the axis 30 of the shaft 88 and relatively thereto.

As shown in Fig. 5 a bearing block 16 is inserted into the outer end of the tubular boom 6| and secured thereto to serve to support the bearings 11 and 18 for the shaft 18. To the outer end 35 of the shaft 18 is keyed a bevel pinion 88 which meshes with a double bevel gear 8| having an upper bevel gear face 82 and a lower bevel gear face 83. The double bevel gear 8| is keyed to the upper end of the shaft 84 which is'journalled 0 in the bearing 86 in the housing 86, the latter being secured to an extension 81 from the bearing block 18 so as to be rigid therewith.

A housing 88 is pivoted to the housing 88 by a circular tongue and' groove connection at 88. 45

This tongue and groove connection serves to interlock the housings 88 and 88 while permitting relative rotation thereof on the axis of the shaft 84. The bevel gears 88'and 8| may be secured to their respective shafts 18 and 84 by means of the 5 nuts 88 and 8|.

At the left-hand end of the housing 88 as viewed in Fig. 5 is a fluid pressure feed cylinder 82 which is held in place on the housing 88 by means of a split ring key 83 seated in an annular recess 55 in the outer surface of the cylinder 82 and engaged circumferentially by the nut 84 which is screw-threaded on the housing 88 at 85. The nut 84 is loose on the cylinder 82 but is provided with an interior shoulder 88 against which the ring key 83 abuts to prevent withdrawal of the cylinder 82 from the housing 88. Movement of the cylinder 82 in the opposite direction is prevented by the key 83 striking against the lefthand end of the threaded tubular portion 81 at the left-hand end of the housing 88 as viewed in Fig. 5.

Splined 6n the arm. shaft as by means of a key 88 having a length approximately equal to the length of the cylinder 82, is a bevel gear I88 7 mounted in the bearing |8| at the right-hand end of the housing 88 as viewed in Fig. 5. The

bevel gear I88 meshes with the bevel gear 82.

On the left-hand end of the shaft 18 is keyed a clutch member I82 which is adapted to be en- 15 gaged by the movable clutch element I 02 which is splined to the driving shaft 80 to rotate therewith but having limited longitudinal movement relatively thereto. By means of eccentric mechanism I04 connected to the movable clutch element I03 the latter may be moved into or out of engagement with the clutch element I02. The eccentric mechanism I04 comprises a circular member extending through a circular opening in the wall of the tube and a cylindrical cup I05 fits in a bracket I06 which is secured to the outer wall of the tube 6|. An operating lever I01 is connected by means '0! a spring I08 to the cup I00 so that the lever I0I may be partially withdrawn. to enable the latter to fit into transverse notches in the bracket I08 to hold the clutch I02, I03 either applied or released.

As shown in Figs. 1 and. 2 a drill socket and holder I08 is secured to the outer end of the feed shaft til and the shank or tail piece of the drill H0 is inserted into the holder I00 to be held thereby for rotation therewith both when the drill is feeding i'orward axially to drill a hole in the upright coal face and when it is being ing lid for controlling the starting, stopping, re-

versing and speed of the motor 25 is connected by means of the electric cable IE6 to the motor Ell as shown in Fig. 4, there being sufilcient slaclr in the cable to permit free movement of the drill unit (it on its pivot Qt through a wide angle so as to enable the positioning of the drill lit at the floor and at the roof in mine chambers of various heights.

When the clutch I t2, m3 is thrown in by means of the lever Itl and the eccentric mechanism lu l and the clutch elements held in coupled relation,

the motor 25 will be operatively connected to the drill lit to rotate the same. The transmis sion of power from the motor 25 to the drill to.

rotate thelatter will be through the reduction sealing 5:3, to, ill and 58 shown in sectional plan view in Fig. 3, thence through the shaft til, the clutch use, IE8, the shaft J9, the bevel gearing 8E9. 32 and Iilfil. to the shaft 98 and the drill sachet I lit.

Mounted on the rear end of the feed shaft 9% is the piston Ill! fitting in the feed cylinder s2. This'piston comprises a sleeve I It which is screw= threaded on the left-hand end of the bearing loloch lit.

The bearing block I It is provided with an annular collar or flange its the left-hand face of which as viewed in Fig. 5 serves as a locking abutment for the right-hand end of the screwthreaded sleeve 'I It. The right-hand lace of the flange I20 is adapted to engage the left-hand end of the cup Ill which holds in place a buffer spring I22 which rests against an annular shoulder in the housing as. An outer annular flange I23 on the cup I25 has a limited movement between spaced-apart annular shoulders in the housing it. When the feed shaft til is in its extreme right-hand position as shown in Fig. 5 the annular flange I20 engages the cup I2I to compress the louder spring I22. When the feed shaft 00 is retracted or moved to the left as viewed in Fig. 5 the spring bufler will be restored to its initial position by the spring I22 moving the cup I2I against its left-hand annular shoulder in the housing 80 as viewed in Fig. 5.

Entirely enclosed within the sleeve I I8 and held in place by the latter and the bearing block H0 is a ball-bearing I24 secured to the left-hand end of the feed shaft 98 by means'of the nut I26. A spacing sleeve I20 on the feed shaft 98 in the housing 08 serves to hold the bevel gear I00 in its bearing I 0|. During feed of the drill into the coal face while such drill is rotating in the proper direction, hydraulic pressure exerted on the left-hand end of the piston Illas viewed in Fig. 5, is transmitted to the feed shaft 98 through the ball-bearing I24. At the outer limit of travel of the feed shaft 98 the buffer spring I22 cushions the stopping of the drill and the annular flange I20 acts on the cup I2I to. seat the latter to limit the travel of the feed shaft 9%. When the drill is retracted by hydraulic suction on the piston ill the pull on the feed shaft 90 is also exerted through the ball-bearing I20 and consequently no appreciable thrust is exerted on the spacing sleeve I26. The left-hand end of the cylinder 02 as viewed in Fig. 5 is closed by a screw-threaded cylinder head I2? which is pro-- vided with a removable screw-threaded plug I '28 for a filling opening. During operation the screw-threaded plug is closed and hydraulic pressure exerted through a flexible hose I29.

An elevating hydraulic motor lid is mounted as shown in Fig. tor the purpose of varying the elevation of the drilling unit 33 on its pivot dd. The cylinder IEBI of the hydraulic motor lilo-is pivoted at It? to as depending bracket plate secured to the bottom oi'the housing The piston rod I34 of the hydraulic motor I 30 is pivot ed at I85 to'thestandard IZ-ltl which is mounted on top of the turntable plate 25. A flexible hose It'll is connected to one end of the cylinder Elli and a flexible hose Hill; is connected to the other end of the cylinder Itl so that hydraulic pressure may be exerted on either side of the piston I39 while the hydraulic pressure on the other side thereof is being withdrawn.

The hydraulic system of control which I prefer to use to prevent interference between the opera tlon of the fluid pressure teed motor and the fluid pressure elevating motor is shown in Figs. 1 and 3. The tank Hill for the supply of fluid pressure medium is shown diagrammatically in Figs. '7 and 8. Such tanlr may be mounted on a platform MI as shown in Fig. 3 and provided with a screw plug M2 for a fillingopening in the top of the tank. A. flexible hose supply pipe its extends from the side of the tank and is connected to the valves which are mounted on the support its shown in plan in Fig. 2.

The valves mounted on the support ltd are diagrammatically illustrated in Figs. 7 and t and comprise a check valve I635 and the manually operated valves Mt, It? and use. Fig. 7 shows the positions of the valves ltd, Ill and its when ill the hydraulic motor I30 is to be operated to ele- Q will produce a flow through the pipe "I in the direction of the arrows I52 through the passageway'1I53 in the valve I48 to the pipe I31 and thence into the cylinder I3I? The flow iromthe cylinder I3I will be through the pipe I38 into the passageway I54 the valve I43 and thence through the pipe I55, and through the passageway I53 into the pipe I51. The latter communicates with the pipe I58 which is connected to the intake side of the hydraulic pump 50. It the hydraulic pump 50 continues to operate aiter the piston I 39 reaches the limit of its stroke the check valve I59 in the by-pass pipe I50 will be opened in the direction of the arrow I3I to protect the hydraulic pump 50.

On account of the displacement of the piston rod I34 on the right-hand side of the piston I33 as viewed in' Fig. 7 more oil will flow through the pipe I31 into the cylinder I3I than flows out of the same into the pipe I38 for a given movement of the piston I33. The operating handle I52 0! the compensating valve I 46 being in a horizontal position as shown in Fig. -'7 the valve I43 will be open. Consequently the operation of the pump 50 during movement of the piston I39 toward the right as viewed in Fig. 7 will draw from the tank I40 through the pipes I43 and I53 a suflicient amount of oil to enable the pump 50 to operateto supply enough oil to keep the left-hand side of the piston I39 completely filled with oil. It will thus be seen that when the pump 50 operates, the supply of the oil for the cylinder I3I at the left oi the piston I39 is drawn partly from the tank I40 and partly from the right-hand side of the piston I39.

When the piston I39 is 'to be moved from its dotted line position to its full. line position the lever I50 is moved to its dotted line position to change the passageways I53 and I54 of the valve I48 to their dotted line positions. When this adjustment is made the valve I41 is left in its full line position shown in Fig. 7. Then upon operating the pump 50 the how will be in the direction indicated by the arrows I52 through the passageway I53 into the pipe I38 and thence into the cylinder I3I to the right of the piston I39.

The flow from the left-hand side of the piston I39 will be through the pipe I31, the passageway I54, the pipe I55, the passageway I53, into the pipe I58, to the intake side or the pump 50. More 011 will now flow from the left-hand side of the piston I 39 than is pumped into the cylinder I3I at the right-hand side of the piston I33, by reason of the displacement of the piston rod I34. The excess oil will flow through the valve I43, the pipe I69, and the pipe I43, back ,to the supply tank I40.

It should be particularly understood that when the valve I41 is in its full line position shown in Fig. '1 the piston ill will be locked against movement in either direction in its cylinder 92. Therefore while the drill unit 43 is being tilted up 'or down on the pivot 44 the drill cannot be moved outwardly or retracted. In like manner when the valve I48 is in its closed position shown in Fig. 8 the piston I39 will be locked against movement in either direction and the drill unit will be held rigidly at adjusted elevation and inclination relative to the turntable 28 during operation of the drill including feed thereof and withdrawal of the drill from the drill hole.

As shown in Fig. 8 the valve I43 is provided with a central passageway I54 which should be moved to the position shown in Fig. 8 before the feed motor is operated. When the elevating mofor I30 is locked by moving the valve I43 to its position shown in Fig. 8 and it is desired to operate the reed motor the lever I43 may be moved to its full line position whereupon the passageway I35 will connect the pipe I55 to the pipe I23 which leads to the feed cylinder 92. Upon operation of the pump 50 the oil will flow in the direction of the arrows I52 into the cylinder 92 to move the piston II1 slowly toward the right as viewed in Fig. 3 to eflect feed of the drill while the same is being rotated by the motor 25 and the power transmission mechanism between this motor and the drill socket I09. I! the drill meets with an obstruction or when the piston II1 reaches the right-hand limit oi. its stroke, continued pressure will be relieved by the flow or oil from the pipe I23 into the pipe I55 and through the check valve I45 whichopens in the direction of the arrow I31 at a pre-determined excess pressure. That is to say, when the pressure in the cylinder 32 exceeds a pre-determined amount oil will flow from the pipe I55 through the check valve I45 into the pipe I58 and thence through the pipe I43 back to the supply tank I 40.

While the piston I I 1 is moving in feeding direction the suction connection between the supply tank I40 and the pump 50 will be through the pipes I43, I53, the passageway I10, and pipes I1I, I58. It should be noted that the compensating valve I43 is shown closed in Fig. 8 while the feed motor is being operated in either feeding or retracting direction.

When the drill is to be withdrawn from the drill hole the handle I43 is moved to its dotted line position as shown in Fig. 8. Operation of the pump 50 will then cause the oil to flow from the pump through the passageway I35'directly to the supply tank I40. The suction side of the pump, however, will be connected through the.

pipes I53, ill, the passageway I10 and pipe I29 to the cylinder 92. to the left of the piston H1. The retraction of the drill is therefore dependent upon hydraulic suction exerted in that portion 01 the cylinder 92 to the left or the piston Ill.

The flexibility or the track mounted drill machine due to the various adjustments that can be made is such that when the shaft 84 is horizontal as shown in Fig. 2 the drill may be ad- :lusted to occupy perpendicular positions relative to the coal lace either at the floor or at the root or at any intermediate point. Or the drill may be inclined either upwardly or downwardly on the axis 84 as well as on the pivot 44. The drill unit 43 may be swung horizontally on the vertical axis 35 shown in Fig. 4 and held in adjusted angular position by the pins I12 inserted through holes I13 in the turntable which register with holes I14 in the horizontal supporting plate 21 on top of the motor frame 25.

However, when the axis 34 is horizontal and the .boom I is in an angular position when viewed in plan the drill IIO must be in a radial position relative to the vertical turntable axis. However, drill holes may be made in horizontal planes in tan-shaped relation at various elevations.

When the axis 34 is vertical the drill may be adjusted to drill holes in fan-shaped relation in various intersecting planes such Ian-shaped relation being relative either to the upright axis 34 or relative to the upright axis of the turntable. The supporting arm or boom 5i being tubular may be made 01' sufllcient length to enable the drill to reach the sides or a working race in a wide room the walls or ribs of which extend a relatively long distance from the longitudinal center iine of the mine track. A reinforcing tube I15 may be connected to the outer end of the housing 84 as shown in Fig. 4 to lend additional support to the tubular boom 6i and the drilling mechanism mounted thereon.

It should be particularly noted that drilling operations may be carried on at the upright face in advance of the mine track so as to obtain drill holes at right angles to the working face and at any point between the floor and the roof and between the ribs or side walls of the entry. When the boom fl is swung laterally on the upright turntable axis 36 it may be swung upwardly or downwardly on the pivot M so as to position the drill holder Hi9 either at the floor or at the roof. Then upon turning the crank lb (Fig. 2) the shaft id (Figs. 2 and 4) may be rotated to operate the worm gearing it, ill shown in Fig. 4. This will effect turning of the tubular boom ti so as to shift the axis at until it is in a vertical plane parallel to the working face. After this adjustment is made the housing as together with the drill may be turned on the axis dd until the drill is perpendicular to the working face. when inclined laterally and downwardly the axis 8 when in an upright position and when in a horizontal position intersects the vertical plane of the coal face. There are two intermediate positions, however, where the axis Ed is in a vertical plane parallel to the vertical plane of the working face.- .These two positions are determined by the intersection of a plane in the circle described by rotation of the shaft 8 3 and housing 8i about the axis of the tube ti and a vertical plane through the intersection between the axis of the tube 69 and the axis of the shaft dd. The

, shaft dd may be brought into this line of inter= and therefore the drill may be adjusted to a position at right angles to the coal face. It will thus be seen that irrespective of the angular position of the boom or irrespective of its lateral position and up or down inclination, the drill may be positioned to drill holes at right angles to the coal face at any point the..eof within the reach of the machine.

When the drilling unit it is turned to adjusted position on the vertical axis of the turntable, it may be locked in such lateral position. When the drilling unit is inclined upwardly or downwardly on its axis i l relatively to the turntable, it may be locked in adjusted position by locking the piston its in the cylinder l3i. Now with the boom Si in a laterally extending position and in an inclined position it may be desirable to drill a hole in the coal face which extends across the space in advance of the mine track, so that such hole will be parallel to the adjacent rib and parallel to the mine track. The hydraulic motor 92 for feeding the drill axiafly is adjustable on rectangularly related axes one of which is the axis of the shaft il i shown in Fig. 5, and the other of which is the axis of the shaft is which is the boom axis. By extending a vertical plane parallel to the working face through the intersection between the axes til and it when the boom extends laterally and is in an inclined position, the correct position of the axis 8% may be ascertained for locating the drill at right angles to the working face. That is to say, by rotating the boom iii until the shaft dd When the boom iii is in an angular posiis at the intersection between such vertical plane and a plane extending through the shaft 84 at right angles to the shaft 79, the axis 84 will be parallel to the working face. In other words, when the boom 6! is in a lateral and inclined position it should be rotated until the shaft 8% is in a verticaLplane parallel to the working face which extends across the space in advance of the mine track. Then the drill may be rotated on the axis 86 until it is at right angles to the working face.

It is preferred to have the boom ti of such length that the tool holder Hi9 will be at such distance from the turntable axis 35 that the side walls may be spaced from the center of the mine track more than three times the width of the track gauge. For instance, if the length of the stroke of the piston ill of the hydraulic feed motor is approximately equal to twice the width of the track gauge and the boom is swung to a position at right angles to the mine track, holes may be drilled in ribs which are located a distance from the turntable axis 36 equal to approximately five times the width of the track gauge. However, the principal advantage in having the boom elongated so that the tool holder we will be located at a distancefrom the turntable axis lit at least equal to three times the width of the track gauge, is to enable the single boom to support the drill for operation at either side of a widecoal face and in positions at right angles to the coal face at any elevation desired and parallel to and adjacent to the ribs or side walls of the entry. It is desirable in many instances to produce the drill holes at right angles to the coal face and adjacent to the ribs so that when the coal is blasted down the walls of the entry will be in alined continuation. Vertical drill holes may also be produced at any point over a wide area of the roof or floor.

While the drill is operated to produce holes in the ribs or in the roof or floor and while the drill is operated in the coal face in a slanting position relative to the upright plane of the coal face, the truck is held stationary on the mine track either by means of the brake mechanism its or by means of sprags blocking the wheels it or by means of roof jacks anchoring the truck frame. But when the drill is adjusted to drill at right angles to the coal face it will be parallel to the mine track and then the drill may be fed by slow traction of the truck either by controlling the motor if or by means of reduction gearing of well known construction. For instance, if the coal is relatively soft faster drilling may be obtained by traction feed of the whole machine along the mine track. When the truck is held stationary on the mine track and the hydraulic motor 92 is used to feed the drill the rate of feed will be automatically regulated when unusually hard material is encountered. When the pressure back of the piston ill builds up to exceed a we determined maximum the relief valve i-iili shown in Fig. 8 will be automatically opened but the drill will continue to rotate until such hard material has been drilled whereupon the rate of feed will again increase until the drill hole has been completed. The arrangement including the hydraulic feed motor is therefore such as to secure varying rates of feed automatically according to the resistance encountered by the drill. Retraction of the drill may be obtained ill) by one continuous rectilinear return movement Z6 of the piston in while the drill is being rotated in cutting direction to cause its spiral guide blades to clean the cuttings out of the drill hole.

Inasmuch as the strokes of the piston II! of the hydraulic feed motor tend to displace the air in the housing 88 openings are provided at I" and I18 in the bearing block 16 and at I18 in the bearing block I80, and an opening is also placed at I8I in the sleeve 6I'shown in Fig. 4. A bleed opening I82 in thehousing 45 permits ingress and egress of air in the tube 6| when the piston III is moved in the cylinder 92. It should be noted that the bleed opening I82 is distant from the working face. Therefore all parts of the feed motor and all parts of the power transmission mechanism between the housing 45 and the drill remain entirely enclosed. By placing the opening I82 distant from the drill the amount of coal dust that can flnd its way into the interior of the drilling unit 43 is reduced to a minimum.

It should also be noted that the controllers I8, H4 and the motors I2, 25 are enclosed in flame-proof casings.

Obviously those skilled in the art may make -various changes in the details and arrangement of parts without departing from the spirit and scope of theinvention as defined by the claims hereto appended, and I wish therefore not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of my invention, what I desire to secure by Letters Patent of the United States is:

1. In drilling apparatus, the combination with a hollow supporting arm, of v a drill, mechanism for rotating said drill, a housing co-acting with said arm to enclose said rotating mechanism, a fluid pressure feed motor comprising a piston the movement of which tends to displace the air in said housing and said hollow support, and means affording ingress and egress of air into said hollow support at a point distant from the working face where the drill operates.

2. Drilling apparatus comprising a fluid pressure motor having a cylinder, a frame for supporting said cylinder, a split ring fitting into an annular groove in said cylinder, and a nut screwthreaded to said frame and having interior annular shoulders for detachably locking said cylinder to said frame.

3. In drilling apparatus, the combination with a supporting frame, of a drilling tool mounted thereon, motor-operated mechanism for rotating said drilling tool, a fluid pressure motor for feeding and retracting said drilling tool, and

means for controlling said fluid pressure motor to effect feeding of the drilling tool by fluid pressure and the retraction thereof by suction.

4. Drilling apparatus comprising an elongated tubular boom, a drive shaft in said boom, a driven shaft in said boom, a clutch between the ends of said shafts and enclosed by the boom, and eccentric mechanism operable from without the boom for connecting and disconnecting said clutch.

5. In drilling apparatus, the combination with a portable support, of a drilling tool, mechanism for rotating said drilling tool, a hydraulic motor for feeding and withdrawing said drilling tool, and means for controlling said motor to operate by hydraulic pressure during feeding of said drilling tool and by suction during the withdrawal thereof.

6. In drilling apparatus, the combination with a truck adapted to travel on a mine track, of a drilling tool adiustably mounted thereon, motor operated mechanism for rotating said tool, and a hydraulic motor operating by pressure to feed said tool and by suction to withdraw the same.

7. In drilling apparatus, the combination with a portable support, of an elongated supporting arm pivotally mounted on said support for swinging movement about a horizontal axis, a drilling too-l adjustably mounted on the outer end of said elongated supporting arm, a motor carried by said elongated supporting arm to move bodily therewith, a fluid-pressure pump connected to said motor and mounted on said elongated supporting arm to move bodily therewith, mechanism operated by said motor'for rotating said drilling tool, means connected between said pump and saiddrilling tool to feed the same axially, and mechanism comprising a fluid-pressure motor'for swinging said arm upwardly and downwardly about its pivot to position said drilling tool.

8. In drilling apparatus, the combination with a self-propelled support, of a turntable mounted on said support for rotation relatively thereto about a vertical axis, an elongated supporting arm pivotally mounted on said turntable for swinging movement about a horizontal axis, a drilling tool carried at the outer end of said arm,

self-contained power-operated mechanism comprising a fluid-pressure pump mounted on said arm to move bodily therewith for operating said drilling tool including rotation and feed themof, and separate mechanism comprising a fluidpressure motor for swinging said arm together with said drilling tool on said horizontal axis.

9. In drilling apparatus, the combination with a self-propelled support, of a turntable mounted on said support for rotation relatively thereto about a vertical axis, an elongated supporting arm pivotally mounted on said turntable for swinging movement about a horizontal axis, a drilling tool carried at the outer end of said arm, self-contained power-operated mechanism comprising a fluid-pressure pump mounted on said arm to move bodily therewith for operating said drilling tool including rotation and feed thereof, and separate mechanism connected to said pump and comprising a fluid-pressure motor for swinging said arm together with said drilling tool on said horizontal axis. 10. In drilling apparatus, the combination with a portable support, of a turntable thereon rotatable about a vertical axis, an elongated boom pivotally mounted on said turntable for adjustment relatively thereto on. a horizontal axis, a drilling tool pivotally mounted on the outer end of said arm, mechanism comprising a fluid-pressure motor for adjusting said arm about said horizontal axis, and self-contained power-operated mechanism comprising a motor and a pump mounted on said arm to move bodily therewith for operating said drilling tool including rotation and feed thereof.

11. A self-contained drilling unit comprising an elongated support, a motor carried by said support, a pump operatively connected to said motor, a drilling tool mounted on said support, mechanism operated by said motor for rotating said drilling tool, and a fluid-pressure motor operatively connected between said pump and said drilling tool to feed the latter axially while said pump is being driven by said first-named motor.

12. Drilling apparatus comprising a fluid-- pressure motor having a piston, a rotary feed shaft, a bearing block, a rotarily screw-threaded connecting flange between said piston and said bearing block, and an abutment collar on said bearing block for clamping engagement by said flange, said piston and said flange and said collar all being of equal diameter.

13. In drilling apparatus, the combination with supporting framework, of a 'drilling tool mounted thereon, motor operated mechanism for rotating said drilling tool, a fluid-pressure motor for feeding said drilling tool, mechanism comprising another fluid-pressure motor for adlusting the position of said drilling tool, a fluidpressure pump, and valves arranged in series and connecting said pump to said fluid-pressure motors for controlling the latter to prevent opera tion of one when the other is operating.

Id. In drilling apparatus, the combination with supporting framework, of a drilling tool mounted thereon, means for rotating said drilling tool, a fluid-pressure motor for feeding said drilling tool, another fluid-pressure motor for adjusting the position of said drilling tool, two valves one for each of said fluid-pressure motors, and conduits for connecting a source of fluidpressure through said valves in series to said fluid-pressure motors so that when one is operating the other may be cut off from such source of fluid pressure.

15. In drilling apparatus, the combination with supporting framework, of a drilling tool mounted thereon, means comprising a fluid-pressure mo= tor for operating said drill, another fluid-pressure motor for adjusting the position of said drill,

valves connected in series for controlling said [I fluid-pressure motors, and conduits connecting a source of fluid-pressure to said fluid-pressure motors so that when either fluid-pressure motor is operating the other may be out ofl from such source of fluid-pressure.

id. in drilling apparatus, the combination with a support, of a drilling tool mounted thereon, means comprising a thud-pressure motor for operating said drilling tool, another fluid-pres sure motor for adjusting the position of said drilling tool, two valves connected in series for con trolling said fluid-pressure motors, and conduits connecting a source of fluid-pressure to said fluid-- pressure motors through said valves to enable one motor to be rendered inoperative while the other is operating and to lock the second named fluid pressure motor in adjusted position while the other fluid-pressure motor is connected to such source of fluid-pressure.

17. In drilling apparatus, the combination with a portable support, of an elongated boom pivoted thereto, a drilling tool mounted on said boom, means comprising a fluid-pressure motor for operating said drilling tool, means comprising another nuid-pressure motor for swinging said boom on its pivotal connection to said portable support, and valves connected in series between a source of fluid-pressure and said motors and operable to effect the operation of only one motor at a time, the other motor being then inoperative by being cut off from such source of fluid-pressure.

it. In drilling apparatus, the combination with a portable support, of an elongated boom pivoted thereto, a drilling tool mounted on said boom, mechanism mounted on said boom for operating said drilling tool, said operating mechanism com= prising a-fiuld-pressure motor, means comprising another fluid-pressure motor for swinging said boom on said pivotal connection to said pivotal support to adjust the position of said drilling tool, two controlling valves one for each of said fluid-pressure motors, and conduits for connecting said valves in series with each other and a source of fluid-pressure to said fluid-pressure motors, said valves being operable to positions to co-act with said conduits to compel either motor to be out ad from such source of fluid-pressure supply when the other is connected thereto.

19. In drilling apparatus, the combination with a portable support, of drilling apparatus mounted thereon and comprising two separate fluid-pressure motors for operating and adjusting the same, two three-way valves one for each of said motors, and conduits for connecting said valves in series with each other and a source of fluid-pressure through said valves to said motors to enable the fluid-pressure medium to pass through both valves when either motor is operated while the 2%. In drilling apparatus, the combination with a support, of a drilling tool mounted thereon,

means comprising a fluid-pressure motor for operating said drilling tool, another fiuid-pressure motor for adjusting the position of said drilling tool, two three-way, valves one for each motor, and piping connection between a source of fluid pressure and said motors through said valves, two passageways in each valve serving for supply and exhaust to and from the corresponding motor and the third passageway in each valve serving to complete the flow line thereby enabling the source of fluid-pressure being cut oil from one motor while the other is operating.

21. In drilling apparatus, the combination with a support, of a drilling tool mounted thereon, means comprising a fluid-pressure) motor for operating said drilling tool, another fluid-pressure motor i.or adjusting the position of said drilling tool, two three-way valves one for each of said motors, and piping connections between a source of fluid-pressure and said motors through said valves, said valves being capable of co-acting with said piping connections to prevent both motorsfrom being'opcrated at the same time, one motor being cut off from such source of fluid-pressure when the other is operating.

22. Drilling apparatus comprising an elongated boom, 9, drive shaft in said boom, a driven shaft in said boom, a clutch between the ends of said shafts and enclosed by said boom, and mechanism operable from without said boom for con meeting and disconnecting said clutch.

23. Drilling apparatus comprising a hollow support, a drive shaft in said hollow support, a driven shaft in said hollow support, a clutch lietween the adjacent ends of said shafts, and mechanisrn operable from without said support for connecting and disconnecting said clutch.

2d. Drilling apparatus comprising a drive shaft, a driven shaft, a clutch between the ends of said shafts, a supporting enclosure for said shafts and said clutch, and mechanism having an air-tight fit in an opening in said enclosure for operating said clutch from without said enclosure.

25. In drilling apparatus, the combination with a portable support, of a drilling tool, mechanism for rotating said drilling tool, a fluid-pressure motor for feeding and withdrawing said drilling tool, a controlling, valve for said motor, and means comprising conduits connected to said valve and motor for edectlngfeed of said drilling tool by fluid-pressure in said motor when said valve is in one position and withdrawalof said drilling tool by suction in said motor when said valveis in another position.

26. In drilling apparatus, the combination with a portable support, of a drilling tool, mechanism for rotating said drilling tool, a fluid-pressure motor for feeding and withdrawing said drilling tool, means for controlling said motor to operate by fluid-pressure during feeding of said drilling tool and by suction during the withdrawal thereof, and by-pass relief valve mechanism for limiting the fluid-pressure in said motor. 2'7. In drilling apparatus, the-combination with a portable support, of a drilling tool, mechanism comprising a fluid-pressure motor for feeding said drilling tool by pressure and withdrawing 'the same by suction, means comprising a valve for controlling said motor, and relief valve mechanism for automatically limiting the pressure in in said motor.

28. In drilling apparatus, the combination with a portable support, of a drilling tool, means comprising a fluid-pressure motor for operating said drilling tool, means comprising an additional fluid-pressure motor for adjusting the position of said tool, said last-named motor comprising a cylinder and a piston and a piston rod connected to said piston and extending from one end of said cylinder, a valve connected to said cylinder to control the flow to and from opposite sides of said piston, a valve for controlling said firstnamed motor, connections between a source of fluid-pressure and said motor through said valves, a suction line, and a valve in the suction line to compensate for the displacement of said piston rod.

29. In drilling apparatus, the combination with a portable support, of a drilling tool mounted thereon, means for operating said drilling tool, means comprising a double-acting hydraulic motor for adjusting the position of said drilling tool, said motor comprising a cylinder with a piston reciprocable therein and a piston rod extending from one end of said cylinder, a pump, supply pipes connected to both ends of said cylinder, a valve for controlling said motor, a supplytank for liquid, branching suction pipes leading to said tank and the suction side of said pump, a valve in the branch leading to said tank, and a pipe adapted to connect that end of said cylinder through which said piston rod extends to both branch pipes to enable said pump to draw from the tank as well as the cylinder when said piston rod is being moved out from said cylinder and said last-named valve is open.

30. In drilling apparatus, the combination with a support, of a drilling tool mounted thereon, means for operating said drilling tool comprising a hydraulic motor, means comprising another hydraulic motor for adjusting the position of said drilling tool, said last-named motor comprising a cylinder and a piston and a piston rod extending from one end of said cylinder, two valves one for controlling each motor, a hydraulic pump, means for connecting said pump through said valves to said motors so that only one motor can be operated at a time, a supply tank for liquid, branching suction pipes leading to said tank and to the suction side of said pump, a valve in the branch leading to the tank, and a pipe connected between said branching pipes and the valve for. controlling the first-named motor, said firstnamed valves being operable to effect operation of said first-named motor when the valve in the tank suction branch is closed and to efiect operation of said adjusting motor when the valve in said tank suction branch is open.

31. A self-contained drilling unit comprising an elongated support, a drill mounted on the outer end thereof, a hydraulic motor for feeding said drill, a pump on the rear end of said support, means extending from the rear portion of said support to the forward end thereof to rotate said drill, and a motor on said support between said pump and said rotating mechanism and operatively connected to both.

32. A self-contained drilling unit comprising an elongated boom, a. supplemental support pivotally mounted at the outer end of said boom, a rotary drill mounted on said supplemental support, a fluid-pressure pump mounted on said support to move bodily therewith and operatively connected to said drill to feed the same axially, means extending from the rear end portion of said boom to the forward end thereof to rotate said drill in its adjusted position, a pump mounted on said boom, and a motor connected to said rotating means and said pump to drive the same.

33. A self-contained drilling unit comprising a main support, an elongated boom rotatably mounted on said support, a pump on said support, a supplemental support pivotally mounted at the outer end of said boom on an axis at right angles to the axis of said boom, a rotary drill mounted on said supplemental support, a fluid-pressure motor on said supplemental support adapted to be connected to said pump and connected to said drill to feed the same axially in adjusted position, means extending from said main support along said boom to said supplemental support for rotating said drill, a motor on said main support connected to said pump and said rotating means to drive the same, and means for rotating said boom and drill relatively to said main support.

34. Drilling apparatus comprising a fluid-pressure motor having a piston and a cylinder, a spring-pressed device comprising a cup and a spring to cushion the stopping of said piston and to start the piston on its return stroke when the pressure on the piston is sufficiently relieved, means comprising an annular flange on said cup slidable along an annular space to limit the compression and expansion of said spring, and means for controlling the operation of said fluid-pressure motor. I

35. Drilling apparatus comprising a fluid-pressure motor having a piston, a rotary and sliding feed shaft, a ball bearing connection between said feed shaft and said piston to enable the latter to travel rectilinearly while said shaft slides and ro-.

tates, a cylindrical cup-shaped extension on said piston, a bearing block fitting closely on said shaft adjacent to said ball bearing, and a cylindrical screw-threaded connection between said cupshaped cylindrical extension and the periphery of said bearing block to enable relative turning thereof on the axis of said shaft to aiford a complete closure for said ball bearing.

36. Drilling apparatus comprising a fluid-pressure motor having a cup-shaped piston, a rotary and sliding feed shaft, a ball bearing at one end of said shaft in said cup-shaped piston, said cupshaped piston being imperforate, and a bearing block having threads therein to provide a connection with said piston to coact with the latter to seal said ball bearing in the enclosure formed by said cup-shaped piston and the threaded connection between the'latter and said bearingblock.

3'7. Drilling apparatus comprising a fluid-pressure motor having an imperforate piston, a rotary andslidingfeed shaft, a ball bearing connection between said shaft and said piston, a bearing block, and a rotary screw-threaded connection between said imperforate piston and said block formed by co-operating threads on each to form a liquid-tight enclosure for said ball bearing.

38. Drilling apparatus comprising a fluid-pressure motor having a cup-shaped imperforate piston, a rotary feed shaft, a thrust ball bearing between said shaft and said imperforate piston, a bearing block, and a rotary screw-threaded connection between said imperforate piston and said bearing block formed by co-operating threads on each to confine said ball bearing to a hermetically sealed chamber.

39. In drilling apparatus, the combination 7 with supporting framework, of a drilling tool mounted thereon, means for rotating said drilling tool, a fluid-pressure motor for feeding said drilling tool, another fluid-pressure motor for adjusting the position of said drilling tool, two controlling'valves one for each of said fluid-pressure motors, and conduits connecting a source of fluid pressure to said fluid-pressure motors through controlling valves connected in series thereby rendering said valves interdependent by compelling ment relative to said support, an elongated boom pivotally mounted on said turntable to swing relatively thereto on a horizontal axis, a drilling tool adjustably mounted on the outer extremity of said boom, a motor and a fluid-pressure pump driven ing along said boom and driven by the said first named motor for rotating said drilling tool, means for controlling connection of said pump to said fluid-pressure motor to efiect axial feed of said drilling tool while being rotated, and motor operated mechanism for swinging said boom on its horizontal axis relatively to-said turntable irre'- spective of the position of the latter relative to said support.

41. In drilling apparatus, the combination with supporting framework, of a drilling tool mounted thereon, motor operated means for rotating said drilling tool, a fluid-pressure motor for feeding said drilling tool and retracting the same in the opposite direction, a fluid-pressure pump, an additional fluid-pressure motor for adjusting the position of said drilling tool relative to said supporting framework, two valves one for controlling one ofsaid fluid-pressure motors, and the other for controlling the other fluid-pressure motor, and conduits connecting said valves in series to enable the adjusting motor to be cut off and locked during the operation of the drill including rotation and feed thereof.

42. In drilling apparatus, the combination with I a portable supporting frame, of a drill support pivotally mounted on said frame to swing relatively thereto on a horizontal transverse axis, a

drilling tool mounted on said drill support, a mo tor mounted on said drill support, power-transmission means between said motor and said drilling tool for rotating the latter, a pump mounted on said drill support and operatively connected to said motor, a fluid-pressure motor connected to said drilling tool to feed the same, a fluidpressure motor pivotally connected at one end to said frame and at its other end pivotally connected to said drill support, and means for controlling the fluid-pressure from said pump to said fluid-pressure motors. I r' 43. In drilling apparatus, the combination with a supporting, frame, of a drill support pivotally connected to said frame on a transverse hori-,

.zontal axis extending across the top of said drill support, a motor mounted on said drill support at the rear end portion thereof, a pump mounted on said drill support at the rear end thereof, a drilling tool mounted on the outer end of said drill support, mechanism connected to said motor for driving said pump, mechanism connected between said motor and said drilling tool for rota ting the latter, a fluid-pressure motor for feeding the drilling tool during rotation thereof, and means for controlling the fluid pressure from said pump to said fluid pressure motor.

44. A drilling unit comprising an elongated boom, tubular means for supporting said boom for rotation on its longitudinal axis, a motor having a frame rigidly connected to said tubular means, mechanism for rotating said boom relatively to said tubular supporting means, a drilling tool mounted on the outer end of said boom, means operated by said motor and extending through said tubular supporting means .for driving said drilling tool, a pump carried by the rear end of said motor, and connected to the latter for operation thereby, a fluid pressure motor for feeding said drilling tool, and means for controlling fluid pressure from said pump to fluidpressure motor.

45. A drilling unit comprising a mot r having a frame and a driving shaft extending from opposite ends thereof. a tubular support secured to. the front end of said motor frame, a pump a d operating mechanism therefor connected to the rear end of said motor shaft and mounted at the rear end of the motor frame, an elongated boom having its rear end rotatably mounted in said tubular support, worm gearing at the outer end of said tubular support for rotating said boom relatively to said support, a drilling tool at the outer end of said boom, means connected between the front end of the motor shaft and said drillconnected to said drilling tool to feed the same during rotation, and means for controlling fluid pressure from said pump to said fluid-pressure motor. 46. A drilling unit comprisin m'otor having a frame, a supporting tube rig diy connected to said, frame, an elongated boo -rotatably supported by said supporting tube, means between said tube and said boom for rotating the latter, a drilling tool mounted on said boom, mechanism between said motor and said drilling tool for rotating the latter, means for feeding said drilling tool, and means for pivotally supporting the drilling unit by suspending said motor frame on an axis extending transversely of the upper side thereof.

4'7. A drilling uniticomprising an elongated boom, a pump mounted thereon, a drilling tool pivoted to the outer end of said boom for adjustment relative thereto on an axis extending at right angles to the axis of said boom, a fluidpressure motor in alinement with said drilling tool and offset laterally from said boom, means mounted on said boom for driving said drilling tool irrespective of its adjusted position relative to said boom, and means for controlling the fluidpressure from said pump to said fluid-pressure motor to operate the latter in any adjusted position of the drilling tool.

48. A drilling unit comprising an elongated boom having a longitudinal passageway therethrough closed from the atmosphere, a drilling tool at the outer end of said boom, a motor, a gear casing connecting said motor to said boom, said gear casing being in communication with said passageway and having a vent to the atmosphere, a fluid-pressure motor connected to said drilling tool, mechanism for connecting the space at one end of said fluid-pressure motor with said passageway, said fluid-pressure motor comprising a piston one side of which effects movement of air along said passageway and through said vent when said piston is moved in opposite directions.

49. In drilling apparatus, the combination with a frame, of a drill support pivotally attached to said frame, a drill mechanism carried by said drill support, an electric motor carried by said drill support, a hydraulic pump driven by said motor, a hydraulic motor for pivoting said drill support with respect to said frame, a second hydraulic motor for feeding said drill mechanism, means interconnecting said motor and said drill mechanism to rotate the latter from the former,

and means for controlling said hydraulic motors from said pump.

50. In drilling apparatus, the combination with a frame, of a drill support pivotally attached to said frame, a drill mechanism carried by said drill support, an electric motor, a hydraulic pump driven by said motor, a hydraulic motor for pivoting said drill support with respect to said frame,

a second hydraulic motor for feeding said drill mechanism, means interconnecting said motor and said drill mechanism to rotate the latter from the former, and means for controlling said hydraulic motors from said pump.

51. In drilling apparatus, the combination with a frame, of a drill support pivotally attached to said frame, a drill mechanism carried by said drill support, an electric motor carried by said drill support, a hydraulic pump driven by said motor, a hydraulic motor for pivoting said drill support'with respect to said frame, means interconnecting said motor and said drill mechanism to rotate the latter from the former, and means for controlling said hydraulic motor from said D p.

52. In drilling apparatus, the combination with a frame, of a drill support pivotally attached to said frame, a drill mechanism carried by said drill support, an electric motor, a hydraulic pump driven by said motor, a hydraulic motor for pivoting said drill support with respect to said frame, means interconnecting said motor and said drill mechanism to rotate the latter from the former, and means for controlling said hydraulic motor from said pump.

EDWARD G. LEWIS. 

